Posts Tagged beer
The secret sauce in Guinness beer?
Posted by mark in design of experiments on August 9, 2024
I highly recommend Scientific American’s May 25 Opinion by Jack Murtagh explaining How the Guinness Brewery Invented the Most Important Statistical Method in Science. It nicely illustrates the t test—a landmark statistical method developed by William Sealy Gosset to assess a key ingredient in Guiness beer for ideal bitterness and preservation—soft resin content in hop flowers. Gosset calculated that a 1% difference in the amount of soft resins in the hops, the best and cheapest being purchased from Oregon,* increased their value to the brewery by almost 11%.
“Near the start of the 20th century, Guinness had been in operation for almost 150 years and towered over its competitors as the world’s largest brewery. Until then, quality control on its products had consisted of rough eyeballing and smell tests. But the demands of global expansion motivated Guinness leaders to revamp their approach to target consistency and industrial-grade rigor. The company hired a team of brainiacs and gave them latitude to pursue research questions in service of the perfect brew.”
– Jack Murtagh
Back in 2017 on National Beer Day, celebrated yearly on April 7 to commemorate the end of USA’s prohibition of its sale, I saluted Gosset and his very useful t-test of the significance of one treatment versus another, that is, a simple comparative experiment.**
“They began to accumulate data and, at once, they ran into difficulties because their measurements varied. The effects they were looking for were not usually clearcut or consistent, as they had expected, and they had no way of judging whether the differences they found were effects of treatment or accident. Two difficulties were confounded: the variation was high and the observations were few.”
– Joan Fisher Box,*** “Guinness, Gosset, Fisher, and Small Samples,” Statistical Science, Vol. 2, No. 1 (Feb., 1987), pp. 45-52
To see how the t-test works, check out this awesome graphical app developed Even Miller. Using Stat-Ease software, I cross-checked it against a case study (Example 3.3) from the second edition of Box, Hunter and Hunters’ textbook Statistics for Experimenters. It lays out a simple comparative experiment by a tomato gardener who randomly splits 11 plants for treatment either with her standard fertilizer (A) or a far more expensive one (B) that supposedly produces far better yields. Here are the yield results in pounds, which you can assess using the t test:
- 29.9, 11.4, 25.3, 16.5, 21.1
- 26.6, 23.7, 28.5, 14.2, 17.9, 24.3
On average the new fertilizer increases the yield by nearly 2 pounds, but is the difference statistically significant? That would be good to know! I have the answer, but it would be no fun to tell you, being so easy to find out for yourself.
PS: Due to the large variation between plants (a greater than 6-pound standard deviation!), this tomato study is badly underpowered. If you do an experiment like this, do anything possible to get more consistent results. Then assess power for whatever the difference is that makes changing fertilizers worthwhile. For example, let’s say that with better plant management you got the standard deviation reduced to 3 pounds and a difference of 4 pounds is needed at a minimum to make the switch in fertilizer cost-effective. Then, using Stat-Ease software’s power calculator, I figure you would need to test 3-dozen plants each in your randomized experiment to achieve an 80% probability of detecting a difference of 4 pounds given a 3-pound standard deviation. I hope you like tomatoes!
*As reported by Eat This Podcast in their 4/10/18 post on Guinness and the value of statistics
***I was very fortunate to meet Joan Fisher Box in 2019 as related in this StatsMadeEasy blog/
Classic case of sensory testing snubbing off a beer snob
Posted by mark in food science on February 26, 2024
The feature story on sensory evaluation in the new issue of ASTM Standardization News brings back a fond memory of a rare victory over an overly smug colleague.
I developed a taste for sensory science as a young chemical engineer determined to prove that mass produced American lagers differed only imperceptibly—consumers being brain washed by deceptive advertisers. This hypothesis drew strong condemnation from one of my colleagues—a chemist named Harold who dissed lesser brews such as Old Milwaukee, which he deemed “Old Swillwaukee”.
To put this beer snob to the test, I organized a tasting at a Super Bowl party attended by a dozen or so fellow researchers. Beforehand, I engaged a sensory professional that our employer hired to guard against “off odors” from our manufacturing plants. She advised that we limit drinking of each beer to a small sip, then eat saltless crackers and wash them down with water before going to next brew. Also, both the presenter of the beer and the taster should be blind to the brand, thus avoiding bias.
However, given my mission to snub a beer snob, we first rated a selection of undisguised beers—including Miller, Budweiser, Old Milwaukee and others (in those days there were no ‘craft’ brews*). Harold rated “Old Swillwaukee” dead last. That was my plan! Then we repeated the tasting with the order re-randomized, but this time not revealing the names. Harold rated Old Milwaukee at the top of his list, thus providing a Super Bowl victory for me (badly needed being a Vikings fan).
My conclusion from this experience, and my work over the years helping food scientists improve the taste and other attributes of their products, is that it would be best to adhere by ASTM’s upcoming revision to Guidelines for the Selection and Training of Sensory Panel Members. For beer and the like, then bear down on the Standard Guide for Sensory Evaluation of Beverages Containing Alcohol (E1879).
We make panelists learn chemical names. For example, isoamyl acetate is a specific compound that smells like candy banana…I make panelists drink heavy cream for mouthfeel attributes. They’re unfazed by whatever we give them anymore because it’s always weird.
– Ali Schultz, sensory manager, New Belgium Brewing Company and leader of the current revision to E1879 (“Accounting for Taste”, ASTM Standardization News, January/February 2024)
However, if you are having a party, it’s more fun to be unprofessional and ignore the mandates to sip and spit, etc. ; )
*PS: The specialty beer brewers are getting a bit out of control nowadays, IMO. For example, I just got an alert from my Stillwater, Minnesota neighborhood microbrewer Lift Bridge to their release this weekend of Taking Care of Breakfast—a “barrel aged imperial breakfast stout aged in 10-year Willet and 6-year Wild Turkey bourbon barrels, infused with peanut butter and banana chips.” This new brew comes in at 12% ABV. Perhaps it may be best to go with orange juice first thing in the morning.
Testing the adage that if you drink beer before wine then you will feel fine
Just in time for the partying hearty for Christmas today, my son-in-law Ryan, a chemist with 3M, alerted me to a statistical study published after last year’s holiday season by the The American Journal of Clinical Nutrition that questioned the advice of grape or grain but never the twain. Naturally, being a drinker of these undistilled alcoholic beverages, I wondered if my tendency to drink beer before dinner and wine for the meal would pass the test. But being a wonk for design of experiments, I was most curious to see a randomized controlled multiarm matched-triplet crossover trial—pictured below for this experiment on the order of addition for beer and/or wine.
Based on results from 90 participants, including a control group, “neither type nor order of consumed alcoholic beverages significantly affected hangover intensity (P > 0.05)”. What really mattered was the total consumption, although, interestingly, hangover intensity did not correlate to breath alcohol concentration (BrAC). However, the authors warn that
“The fact that we did not find a direct correlation between maximal BrAC and hangover intensity should not be misinterpreted as an invitation to drink until the cows come home. Likely, this correlation overall does exist but is not directly apparent in the narrow range of peak alcohol levels studied here.”
It’s disclosed at the end that Carlsberg provided the beer (premium Pilsner lager recipe from 1847) free of charge “for the sole purpose of utilization in this study”. Although I trust the author’s disclaimer of any bias, perhaps further study is warranted with stronger beers such as a Belgian trippel. Maybe wine would then be best drunk first. To be continued…
A century after prohibition began, Minnesota still limits beer
Beer and statistics are a pairing that began in the early 1900s with Gossett and his work at Guinness brewery to develop the t-test. Fisher’s landmark book The Design of Experiments featured an innovative arrangement of beer-destined (presumably) barley in field trials at the Rothamsted station in 1927. George Box, who invented response surface methods in 1951, gained further fame by hosting Monday night beer sessions that inspired adoption of statistical methods by budding scientists. Therefore, beer is a suitable topic for a blog on statistics, particularly one that maintains a wry tone. That’s my position and I’m sticking to it.
Today Utah increased their allowance for alcohol content in beer, leaving my State of Minnesota as the last in the nation to limit grocery stores to 3.2 percent by weight (equivalent to 4% ABV—alcohol by volume—the standard measure reported by modern brewers). Minnesota did loosen up restrictions on microbreweries to allow food trucks. The State also eliminated the ban on selling liquor on Sunday. However, it’s annoying that beer (other than the 3.2 swill), wine or other alcoholic beverages cannot be bought when shopping for food.
It was a Minnesotan, Andrew Volstead, who authored the Act that enforced of the 18th Amendment to the Constitution prohibiting the sale and drinking of alcohol. The Volstead Act passed on October 28, 1919 when the Senate overrided President Wilson’s veto. The Cullen-Harrison in 1933 led to the legalization of 3.2 beer on April 7th–now known as National Beer Day. Later that year the 21st Amendment repealed prohibition, but many States held on to 3.2 beer as a compromise for those like Volstead who remained committed to temperance.
I look forward to the day when Minnesota opens up the sale of “full point” beer and 3.2 becomes a relic of the last century. Nevertheless, it’s good to remain mindful of the effects of higher ABV beer on the brain, which I’m reminded of by this tableau of favorite coozie, can and bottle on my desk at home. (My granddaughter Laine taped up the warning sign.) Not finding Brain’s Bitter (Cardiff, Wales) or Skull Splitter (Orkney Islands) readily available, I am currently drinking Founder’s Mosaic Promise—a single-hop ale at 5.5% ABV brewed in Grand Rapids, Michigan. It’s tasty! Cheers for real beers!
Excessive intake of alcohol kills brain cells. But naturally, it attacks the slowest and weakest brain cells first. In this way, regular consumption of beer eliminates the weaker brain cells, making the brain a faster and more efficient machine. And that, Norm, is why you always feel smarter after a few beers.
– Cliff Clavin, Cheers
National Beer Day–A fine time for fun facts and paying homage to a wickedly smart brewer from Guinness
Yesterday marked the end of American prohibition of beer in 1933, albeit only up to 3.2% alcohol by weight. This date every year in the USA has become a day to endorse President Roosevelt’s observation at the time that “I think this would be a good time for a beer.”
It’s also a great time to pay homage to master brewer William S. Gossett of Guinness–the “student” of the Student’s T-Test, a method for extracting the essence of discovery from small samples of data, such as that he generated from his experiments on dry stout. For the whole story, see this wonderful writeup by Priceonomics on The Guinness Brewer Who Revolutionized Statistics.
“He possessed a wickedly fertile imagination and more energy and focus than a St. Bernard in a snowstorm. An obsessive observer, counter, cyclist, and cricket nut, the self-styled brewer had a sizzle for invention, experiment, and the great outdoors.”
– Stephen Ziliak
Glory to Gossett—a brilliant boffin of beer! Beyond recognizing him, here are other fun facts and figures that I gleaned from the International Business Times from their post yesterday on National Beer Day :
- If an empty beer glass makes you fearful, you suffer from Cenosillicaphobia. Say that after having a few.
- Women “brewsters” pioneered beer making 5,000 years ago. Let’s tip our caps to these wonderful ladies.
- Guinness estimated that at one time about 93,000 liters of beer was lost in the beards of Englishmen every year. Gross! Along those lines a brewmaster in Oregon developed a brew using yeast collected from his own beard. Yuk!
- In ancient Babylon if a person brewed a bad batch, he was drowned. Come on, lighten up!
Cheers for beers!
Cheers for Czech beers
This is the view of the Charles Bridge in Prague from the usual vantage point of a fellow like me who likes his beer. As reported here by Radio Prague, the Czech Republic leads the world by drinking 160 liters per person per year. With half liter cans of Urquel going for less than 35 Crowns–only about $1.50 in US dollars, I can see why this alcoholic brew has achieved such popularity in this country. Bottoms up!
A fine beer may be judged with only one sip, but it’s better to be thoroughly sure.
-Czech Proverb
Extreme brews and better ones that stay within more-reasonable limits
Posted by mark in pop, Uncategorized on October 26, 2014
While in Antwerp last week I sampled many good beers but none as good as the Trappist-brewed Orval pictured.
The locals love it so much that demand far exceeds supply from the ever-shrinking ranks of monks who brew it at the monks at the centuries-old Abbey of Notre Dame d’Orval. It is lip-smacking good, or as the Belgians in this Dutch-speaking region say—smakelijke.
On the flight home I watched several episodes of Brew Dogs, which features a pair of zany Scots who go for extreme craft beers. For example they took a blond Belgian ale and freeze distilled it many times to a level of 55 percent alcohol by volume (ABV)—a new record for beer. However even with it being infused with nettles from the Scottish Highlands and fresh juniper berries, this over-the-top brew must go well beyond the bounds of good taste.and … then put in a bottle created by a taxidermist.
A few years ago I headed over the border to Hudson, Wisconsin* to pick up a bottle of the then record-holder for ABV at a now-paltry 22 percent**—Dogfish Head’s World Wide Stout. With some coaching from my number one son, I poured it into a brandy-glass and sedately sipped it. I rate it zeer smakelijke. However, I am happy to go for far more reasonably high ABVs of 8 percent or so that come with tripel Belgian abbey ales. A few mugs of that provide a very good buzz. Proost!
*Many great beers do not achieve distribution in Minnesota due to liquor not being allowed for sale on Sundays and especially not growlers of craft-brews—all this being defeated again in May by State Senate. It seems that hell will freeze over and the Vikings will win the Superbowl before we can drink on Sundays. Until then it’s on Wisconsin.
**See this beer well down the BeerTutor.com list of strongest beers in the world.
Not the usual boring statistics conference—attendees called to duty for developing an optimal blend of beers
Earlier this month I attended the 5th European Design-of-Experiment User Meeting in Cambridge, England, which, considering the topic being statistical design of experiments, turned out not to be as dull as one might think. All the credit for the pizzazz goes to our colleagues across the Atlantic—PRISMTC; in particular Paul Nelson and Andrew Macpherson. They conjured up an in-conference experiment that developed an optimal blend of three local beers (all made by Milton Brewery and sold in bulk by Polypins (36 pints) from £56, Firkins (2 polypins) from £84), a pale ale called Cyclops (30-80%), a bitter under the label Justinian (20-70%) and a dark mild named Medusa (0-50%). Prior testing by these two boffins of stats and zymurgy (that is, the study of yeasty concoctions) led them to constrain the ranges of the three brews to the ranges shown in parentheses.
Paul and Andrew laid out a clever design that, via balanced incomplete blocking, restricted any one taster to only 4 blends, while testing enough combinations often enough to provide adequate power for discerning just the right formula. The fun bit was them asking us conference-goers to provide the necessary data prior to an atmospheric dinner at Magdalene (for some reason pronounced in English as “maudlin”) College.
This limitation on beer was one departure from a similar mixture experiment on beers that I ran* with my two sons and son-in-law as the tasters (little chance them going along with such a sensible restriction). The other wrinkle was them requiring all of us to taste a strip of paper that ferreted out about a third of the tasters being “super tasters”—those who immediately recoiled from the bitter taste (many thought it just tasted like paper).**
It turned out that the bitterest blend, in contrast to the mildest of the beer mixtures, was not greatly liked. I think this must be an acquired taste! You can see this on the triangular, 3D response surface graph of the predicted response—the lowest corner being the B:Bitter. Surprisingly, mixing in some A:Ale makes a relatively tasty brew—these two beers synergize, that is, provide much better results than either one alone. But the tastiest blend of all is the peak at the C:Mild corner, with 30% of Cyclops, 20% of Justinian and 50% of the Medusa, some blends on a ridge through the middle of the triangular mixture space look promising.
Three cheers for three beers and hats off to the brilliance of Paul and Andrew of PRISMTC for pulling off this fun, clever and informative taste test. See their full, illustrative report here.
*See Mixture Design Brews Up New Beer Cocktail—Black & Blue Moon
**Check out this BBC report and short video on testing for super tasters
Machine provides the perfect pour for Japanese beer
Awaiting a flight out of Japan’s Narita Airport, I came across this beer-pouring machine in the Delta lounge. See it in action here. It turns out that there’s a science to pouring beer as I reported in this article explaining how UK Boffins Pull Off Brilliant DOE on Beer. The only drawback of this machine is that it lacks conversational skills. I found it a bit awkward sitting there with my perfectly poured beer and no one to talk to while enjoying it. 🙁
Slugging down beer—which brew preferred by shell-less terrestrial gastropods
Inspired by my new web-based “Launch Pad” to the book DOE Simplified, PhD biologist Gaston Habets put his new statistical know-how to good use in his own backyard out in California by offering a choice of beer to the slugs eating up his garden.
Being a native of a cold clime I’d no idea how troublesome slugs could be until some years ago when my cousin in the Bay Area had me out to her place for dinner and asked me to help her gather up greens from the garden. The size of the slugs surprised me: The Pacific banana slug approaches a foot in length according to this New York Times science blog.
Given their gentle nature and top speed of 0.0055 miles per hour, one need not fear these slimy creatures. The only thing is that they eat up the gardens. So that sets the stage for the humane solution of sidetracking slugs with a bowl of beer. But which brew do they prefer? Gaston did his bit for the sake of garden science by setting out eight trays at specific locations around the vegetables and randomly pouring either Bud light or alcohol-free O’Doul’s. He repeated this experiment over four nights in a way that blocked out any differences in the nocturnal feedings.* The graphic shown here shows the outcome: By nearly a 3-to-1 ration slugs preferred Bud Light over the O’Doul’s. They did not get thrown off by the random location of the beer—the slugs found their favorite bars and bellied up.
*Gaston’s data showed a maximum slug count on Saturday night, but then they dropped off to a minimum on Sunday. My conclusion is that slugs party hearty. Who knew?
Slugs prefer Bud Light over O’Doul’s
P.S. It seems that slugs from coast to coast really do prefer Bud from what I see here.